Physics Practical

The Physics Practical is Paper 3 of the SSCE Physics Examination, carrying a total of 50 marks. In WAEC, the objective paper is worth 50 marks, while the essay is worth 60 marks. For NECO, both the objective and essay papers carry 60 marks each. The Physics Practical consists of three questions, and students are required to answer two out of the three. Each question carries 25 marks.

Every question is divided into two parts: (a) and (b). The (a) part, which carries 21 marks, involves conducting an experiment, taking readings, tabulating results, plotting graphs, calculating slopes and/or intercepts, and interpreting results. Additionally, students must state two precautions taken to ensure accurate results. The (b) part, worth 4 marks, consists of short essay-style questions based on the theory behind the experiment or related topics.

Question 1 typically covers mechanics, Question 2 is usually from optics or heat, and Question 3 focuses on electricity.

The Experiment

Apart from mathematical instruments, all necessary apparatus for the experiment will be provided. The diagram of the setup in the question paper serves as a guide for arranging the apparatus. Follow the procedure given in the question paper to conduct the experiment, but do not copy the diagram or procedure, as it is unnecessary. The most important aspect is presenting a table of values containing your readings.

Readings

Since the examiner is not present to observe the experiment, they will assess your performance based on your recorded readings. Marks for conducting the experiment are tied to the accuracy and consistency of your data. The only way to prove that you performed the experiment is by ensuring that your data is consistent.

  1. Your values should be to the same decimal point.
  2. Tabulate your reading in a neat and tidy matter. Excessive cancellation will subtract your marks
  3. The heading for your table should include units

Displaying Data Using Graphs

Graphs are plotted to show the relationship between two quantities. The independent variable is usually plotted on the x-axis, while the dependent variable is plotted on the y-axis.

Guidelines for Plotting Graphs

  1. Use a pencil to allow for easy correction of mistakes. Erase any mistakes properly.
  2. The graph should have a clear title in the format:
    "Graph of (dependent variable) vs (independent variable)"
    Example: Graph of Distance against Time.
  3. Label the axes clearly with units in the format: "quantity / unit".
    Examples: distance / cm, time / s.
  4. Use appropriate scales for the axes. An appropriate scale should be easy to use, such as multiples of 2, 5, or 10. The scales should also allow the plotted points to take up more than half of the grids provided.
    Examples: 1 unit = 20 cm, 1 unit = 4 s, 1 unit = 500 cm², 1 unit = 0.2 N.
  5. Axes need not start from 0.(Unless Specifically Stated) As a general rule, the plotted points should take up at least half of the area provided.
  6. Plot points with a pencil and mark them with a small sharp cross (*).
    Avoid using a dot (•).

Drawing a Best Fit Line or Curve

When instructed to draw a best fit line or curve, follow these guidelines:

  1. Do not connect the plotted points directly. Instead, draw a best fit line or curve that represents the overall trend.
  2. A best fit line should be a single, continuous line. It should be smooth and not have any sudden changes or bumps.
  3. A best fit curve should also be smooth, without sharp angles or kinks.
  4. The best fit line or curve should pass as close to as many points as possible. Ideally, there should be an approximately equal number of points above and below it.
  5. Handle irregular points carefully. If any data points are significantly far from the best fit line or curve, consider repeating the measurement or calculation. If the point is an error, circle it and label it as an "anomalous point."

Electricity Precautions

  1. I ensured that all electrical terminals were securely connected to prevent partial contact.
  2. I avoided parallax error when reading the voltmeter.
  3. I used short connecting wires to minimize resistance and conserve battery energy.
  4. I kept the circuit open when not taking measurements to prevent the battery from draining.
  5. I checked for and avoided zero error in the voltmeter readings.

Simple Pendulum Precautions

  1. I displaced the pendulum bob through a small angle to maintain uniform oscillations.
  2. I ensured that the motion was not conical to maintain accurate measurements.
  3. I avoided parallax error when using the meter rule.
  4. I checked for and avoided zero error in the stopwatch to prevent systematic errors.
  5. I took repeated measurements to reduce random errors.
  6. I ensured windows were closed and fans were turned off to prevent external air disturbances.

Light and Optics Precautions

  1. I avoided parallax error when reading the meter rule.
  2. I ensured that the objects, lens, and screen were properly aligned for accurate measurements.
  3. I cleaned the lens to obtain a clear image.
  4. I positioned the lens vertically in the lens holder.
  5. I ensured that a sharp image was formed before recording my measurements.
  6. I closed the windows and used a curtain to eliminate external light interference and enhance image clarity.

Moment of A force Precautions

  1. I ensured avoided parallax error when taking reading
  2. I ensured suspended mass did not touch the table
  3. I noted zero error on the meter rule